Abstract: Shape memory alloy(SMA)is a new smart material. Besides shape memory effect(SME), this material also exhibits pseudo-elasticity(PE)and higher energy dissipation factor. In this paper, SMA damper is designed and made based on PE of SMA, the capability of this damper is tested. The results indicate that:(1)SMA dampers exhibit significant damping capability; the maximum value of the average equivalent viscous damping ratio can reach 33.56%, the minimum value is 14%; it can suit preferably to the passive control of structure vibrations.(2)The damping capability of SMA damper depends on the load frequency; the damping capability is better in lower frequency; the damping capability descends gradually when the load frequency is increased.(3)The damping capability is also dependant upon the stroke of SMA damper; the average equivalent viscous damping ratio is less when the stroke is either too small or too large; the maximum equivalent viscous damping ratio is acquired when the maximum stroke is 1/2 of its limit value.(4)The stress-strain curve of SMA damper shows itself holistic upward excursion when it is loaded cyclically, agreeing with the available test results.(5)The test results conform with the theoretical results very well.